Your ignition may or may not be original. It sounds, like you said, it will be fairly simple.
The problem is, I don't know if you have what is called a "one wire" alternator hookup or a "three wire". I will give the three wire version. Maybe you can describe all the wires you see coming off the alternator. I DO NOT CARE WHAT COLORS you have. DO NOT focus on colors, focus on how it's hooked up from one end to the other. Colors get changed by previous owners.
Some alternator are NOT designed for one wire. If you have only one big wire to alternator, you have a one wire. If you have the "1" and "2" connection also hooked up, you have a three wire. I am assuming you DO NOT have a separate voltage regulator. You must advise these things to get proper advise.
So, You have a big gauge wire from battery to the positive lug on alternator. That wire can come from the starter lug or direct from battery post. There is a smaller jumper wire from that alternator positive lug to alternator terminal marked "2". Then you have a wire from alternator terminal marked "1" to the ignition switch "ON" terminal or to a idiot light bulb, thru bulb to Ign ON terminal.
You have a wire from ignition "SOL" or "START" terminal to solenoid "S". "R" on solenoid may or may not be hooked up....and of course a big wire from battery to starter lug ("BATT"). You will have a direct power wire to your ignition switch "batt" terminal. This wire should have a fusible link inline to act as a fuse.
Take off the white ceramic ballast resistor you found and put it in a drawer.
I do not know what fuse panel you have, old or new, so I can't go further with the rest of your wiring of lights and all that. Basically the ignition "ON" also has a wire to the fuse panel to "turn it on" and supply power, thru fuses, to various components. The headlight switch has a direct battery wire also, to distribute to all the lights.
Any wire you disconnect during this, just tape over the end until you find out if they were need or not. You may have to break down and open up your harness and redress it.
You may want to read all you can about general wiring. We all knew nothing at one point. Everything is fused. Everything has a switch. Components get a hot wire to them (thru a switch) and are ground by their screws or bolts or by touching the chassis or body or motor. The entire truck is the return line to the battery negative post. Provided you have a cable from battery negative to motor and; flexible braid straps from motor to body and from body to frame.
